1. Field of the Invention
The present invention relates to web browser control of audio operations for voice enabled web applications within a hypertext markup language (HTML) and hypertext transport protocol (HTTP) framework.
2. Description of the Related Art
The evolution of the public switched telephone network has resulted in a variety of voice applications and services that can be provided to individual subscribers and business subscribers. Such services include voice messaging systems that enable landline or wireless subscribers to record, playback, and forward voice mail messages. However, the ability to provide enhanced services to subscribers of the public switched telephone network is directly affected by the limitations of the public switched telephone network. In particular, the public switched telephone network operates according to a protocol that is specifically designed for the transport of voice signals; hence any modifications necessary to provide enhanced services can only be done by switch vendors that have sufficient know-how of the existing public switched telephone network infrastructure.
FIG. 1 is a diagram illustrating the existing public switched telephone network. As shown in FIG. 1, the public switched telephone network 10 includes a wireline subnetwork 12, a wireless subnetwork 14, and a time division multiplexed (TDM) backbone subnetwork 16 configured for transporting voice data and other data between user devices 18 according to the existing public switched telephone network protocols. The subnetwork 16, for example, includes interexchange trunks for transporting voice data between interexchange carriers and/or local exchange carriers.
As shown in FIG. 1, the wireline subnetwork 12 includes telephony application servers 20 configured for providing voice applications 22 such as subscriber profile management, voice mail, call forwarding, etc. for the user devices 18a, 18b, and 18c coupled to the wireline subnetwork 12. As recognized in the art, the telephony application servers 20 include advanced intelligent network (AIN) components such as services control point (SCP) directories and service nodes (SN) configured for controlling the telephony applications 22. The wireline subnetwork 12 also includes telephony access services 24 configured for providing the user devices 18a, 18b, and 18c access to the wireline subnetwork using, for example, analog twisted pair connections or ISDN connections to a central office. The user devices 18a, 18b, and 18c, illustrated as a cordless telephone 18a, a fax machine 18b with an attached telephone, and an analog telephone 18c, are referred to herein as “skinny clients”, defined as devices that are able to interface with a user to provide voice and/or data services (e.g., via a modem) but cannot perform any control of the application 22 or the protocol used to interface with the wireline subnetwork 12.
The wireless subnetwork includes wireless application servers 26, and wireless access services 28 for providing wireless voice and data services to the wireless user devices 18d, 18e, and 18f. The wireless user devices 18d, 18e, and 18f, illustrated as a cellular telephone (e.g., AMPS, TDMA, or CDMA) 18d, a handheld computing device (e.g., a 3-Com Palm Computing or Windows CE-based handheld device) 18e, and a pager 18f, interact with the wireless application 30 based on respective wireless protocols controlled by the wireless access services 28. The wireless application servers 26 control wireless services such as home location register (HLR) management, and service node (SN) telephony applications. “Tiny clients” are distinguishable from skinny clients in that the tiny clients tend to have even less functionality in providing input and output interaction with a user, and may not be able to send or receive audio signals such as voice signals at all. Examples of tiny clients include wireless user devices 18d, 18e, and 18f, as well as function-specific terminal devices. Note that tiny clients tend to be one-way (receive-only or transmit-only) devices.
In both cases, however, both skinny clients and tiny clients have no control of the respective applications 22 and 30 that are running within the respective networks. Rather, the applications 22 and 30 are executed exclusively by the servers 20 and 26. Moreover, both skinny clients and tiny clients have no control of the access protocol used to access the respective subnetworks 12 and 14; hence, the skinny clients and tiny clients are currently incapable of initiating access to another network using an alternative protocol, for example Internet protocol (IP). Consequently, the skinny clients and tiny clients rely exclusively on the service nodes of the servers 20 and 26 to provide the voice application services programmed in the applications 22 and 30, respectively. Although this exclusive control of the applications 22 and 30 by the servers 20 and 26 is advantageous in maintaining control over quality of service and reliability requirements, the applications 22 and 30 can only be developed and maintained by programmers having sufficient know-how of the public switched telephone network infrastructure. As a result, programmers familiar with open standards such as IP are unable to provide contributions in enhancing the applications 22 and 30 due to the limitations of the public switched telephone network paradigm.
FIG. 2 is a diagram illustrating the web client-server paradigm of an open standards-based IP network 40, such as the World Wide Web, the Internet, or a corporate intranet. The IP network 40 provides client-server type application services for clients 42a and 42b by enabling the clients 42 to request application services from remote servers using standardized protocols, for example hypertext transport protocol (HTTP). For example, the client 42a is a stand-alone personal computer or workstation that has its own application 44 for providing its own application services. The client 42a can access a remote web application server 46 that executes a different set of application services 48 via an IP-based packet switched network 50 using either remote access services 52 or local area network access services 54, if available. Similarly, the client 42b having only a browser 56 can also enjoy the services of the applications 44 and 48 by accessing the respective computers 42a and 46.
The clients 42a and 42b, referred to herein as “fat clients” and “thin clients”, respectively, have the distinct advantage that they can initiate requests using IP protocol to any connected web server 46 to execute part or most of the applications 48 on behalf of the clients. An example of a fat client 42a is an e-mail application on a PC that knows how to run the application 44 and knows how to run the IP protocols to communicate directly with the messaging server via the packet switched network 50. An example of a thin client 42b is a PC that has a web browser; in this case, the web browser 56 can use IP protocols such as HTTP to receive and display web pages generated according to hypertext markup language (HTML) from server locations based on uniform resource locators (URLs) input by the user of the PC.
Hence, the web server paradigm enables the clients 42 to access any web server on the IP network 40. Moreover, the use of open protocols such as HTTP and HTML enable any client 42, regardless of its configuration, to access an HTML web page from a server that has no knowledge of the configuration of the requesting client; if the HTML web page received by the client includes information such as a specific HTML tag that is not recognizable by the browser 56, the browser 56 can merely ignore the unrecognized HTML tag.
Efforts at extending the voice applications 22 and 30 from the public switched telephone network to the IP network 40 have had limited success, primarily because the telephone protocols used in development of the applications 22 and 30 do not operate under the same paradigm as the IP network 40. For example, the telephony applications 22 and 30 are state aware, ensuring that prescribed operations between the application servers 20 or 26 and the user devices 18 occur in a prescribed sequence. For example, operations such as call processing operations, voicemail operations, call forwarding, etc., require that specific actions occur in a specific sequence to enable the multiple components of the public switched telephone network to complete the prescribed operations.
The applications 44 and 48 running in the IP network 40, however, are state-less: the applications 44 and 48, in response to reception of a specific request in the form of a URL from a client 42, instantiate a program configured for execution of the specific request, send an HTML web page back to the client 42, and end the program that executed the specific request. Although state information may be passed between the browser 56 and a web application 48 using a data file referred to as a “cookie”, some users prefer not to enable cookies on their browser 56; in addition, the passing of a large amount of state information as would normally be required for voice-type applications between the browser 56 and the web application 48 would substantially reduce the bandwidth available for the client 42.
In addition, HTML does not provide the type of control that is necessary to support voice applications. Specifically, HTML was designed as a set of specifications for embedding instructions within text that specifies to a browser how the text should be presented to the user. Hence, HTML is particularly effective for presenting on a browser a web page having text and image data, or forms data. However, HTML does not provide good media control: if instructions are embedded within an HTML page, there is no guarantee that a browser will execute the embedded instructions as intended by the web page designer.
Hence, efforts have been made to integrate the telephony applications 22 and 30 directly onto the IP network 40 by developing protocol translators that provide a termination between the telephony applications servers 20 and 26 and the web application servers 46. One such proposal is referred to as voice over IP, where telephony data from the telephony applications 22 and 30 are repackaged into IP packets for transmission across the IP network 50. These efforts, however, still require programmers who have substantial know-how of the telephony applications 22 and 30 and the public switched telephone network infrastructure. Moreover, the repackaging of telephony data into IP packets creates substantial problems in transmission of the telephony data, since the transport of IP data packets is not sequential and synchronous, as required for the voice applications.
Another attempt at performing voice applications over an IP network involves rewriting the telephony applications 22 and 30 as scripts in extensible markup language (XML), and sending the XML scripts over the IP network to an interpreter that is coupled to a telephone. The interpreter then plays the received XML scripts for the telephone. However this approach merely transfers some application functionality from the telephony applications 22 and 30 to the interpreter, and still requires telephony application engineers to write XML scripts of the applications 22 and 30. Hence, the IP network is used only for transporting the XML scripts, and does not take advantage of the open standards-based flexibility of the IP network that has provided enormous growth in web infrastructure and Internet commerce.